Geometry by Kyle Gann

Here are the movements of my microtonal three-Disklavier piece Hyperchromatica written after the commercial CD was released.

Geometry (Homage to Schillinger) is in at least one sense it is my most minimalist work, based on short repeating phrases going out of phase with each other (except for a section just past the midpoint, in which the ostinatos are rather long). Each repeating phrase contains notes in several octaves, so that the ear can't keep the simultaneous repeating figures separate - something like an audio analogue of Op Art.

"Extravehicular Activity" is NASA's official term for a spacewalk. Everything here is in the piano's upper-half register except for a repeating D way down below.

Delta Oracle is notated almost completely in quarter-notes, with a different tempo on every beat for long passages, following a quasi-exponential tempo scale. This provides for an unmetrical rhythm that reminds me of the more flexible and nuanced rhythm of declamatory speech.

2.7 Kelvin is couched almost entirely in minor and German sixth chords and uses some close dissonances written in for a variety of types of resonance.

The Insomnia of Lilacs is the piece I wrote after Hyperchrmatica. It is a half-hour tone poem using 58 pitches per octave. It occurred to me that a lot of pitches might be conveniently handleable if I had multiples of the same instrument(s) tuned to the same scale, but at different transpositions. So I came up with an ideal chamber ensemble of flutes, vibraphones, and pianos using a set of parallel scales. Having just spent two years on the harmonic series (Hyperchromatica), I was desperate to have minor tonalities again, and especially to move smoothly between major and minor seventh chords. The resulting 11-limit scale has a 12-pitch scale built up on five separate tonics, resulting in 58 pitches per octave. A Copland quote appeared inadvertently; I embraced it and played with it. Two Europeans, Eberhard Weber and Arvo Part, make momentary appearances, and the spirit of Harold Budd hovers. As for the title, I wanted to evoke fragrance and nighttime, with a tinge of surreality that relates to the strange voice-leading among the tonalities.

Way, way more information, including the tuning, here:

https://www.kylegann.com/Hyperchromatica.html

https://kylegann.com/InsomniaofLilacs.html

Kyle Gann (b. 1955 in Dallas, Texas) is a composer and the author of seven books on American music, including books on microtonality, Charles Ives's Concord Sonata, John Cage's 4'33", Conlon Nancarrow, and Robert Ashley. He studied composition with Ben Johnston, Morton Feldman, and Peter Gena.